图像信号处理中的合并和子采样有什么区别?

What is the difference between Binning and sub-sampling in Image Signal Processing?

据我所知,CMOS图像传感器ISP(图像信号处理器)中有一些功能。 具体来说,我想知道合并和子采样之间的区别。我认为这些目的与减小图像尺寸相同。 但是,我不确定为什么存在这些功能? 他们的目的是什么?

Binning 和 sub-sampling 如您所想的那样减小了图像尺寸,但它们关注的是不同的东西。让我们分别解决每个问题

合并

图像处理中的合并主要处理 quantization. The closest thing I can think of is related to what is known as data binning。基本上,考虑将您的图像分解成不同的(非重叠的)M x N 个图块,其中 MN 是图块的行和列,MN 应该比图像的行和列小得多。

如果您考虑 M x N 像素的任何网格,所有这些像素都将替换为具有代表性的颜色。这个代表色的计算方式有很多种...平均是一种流行的方法。执行分箱的原因主要是作为一种数据预处理技术,用于减少微小观察误差的影响。这有效地减少了代表图像的信息量,因此它通过减少代表图像的独特颜色的数量肯定减小了图像大小。

此外,对数据进行分箱也可以减少影响 CMOS 传感器的噪声对最终处理图像的影响,但代价是颜色的动态范围较低。

二次抽样

图像处理中的子采样主要处理图像大小调整。它也被称为image scaling. The goal is to take an image and reduce its dimensions so that you get a smaller image as a result. Binning deals with keeping the image the same size (i.e. the same dimensions as the original) while reducing the amount of colours which ultimately reduces the amount of space the image takes up. Subsampling reduces the image size by removing information all together. Usually when you subsample, you also interpolate or smooth the image so that you reduce aliasing

子采样在视频处理中还有另一个应用 - 特别是在 MPEG where video is encoded in YCbCr. Y is the luminance while Cb and Cr are the chrominance pairs. We tend to notice changes in luminance rather than chrominance, and so the chrominance is subsampled to reduce the amount of space taken up by the video. Specifically, the human visual system has poor acuity when it comes to colour information than we do with luminance / intensity. Usually, the chrominance values are filtered then subsampled by 1/2 or even 1/4 of that of the intensity 中。即使使用相当高的子采样率,我们也没有注意到感知图像质量方面的任何差异。


这显然是对它们之间差异的相当粗略的介绍,但我希望这能让您充分了解您所追求的目的。

祝你好运!